HP from exhaust

Most will say no. I ditched the cat and it feels faster / more responsive.

 

If the original is restricted, then yes you can get a few ponies from an aftermarket free flow exhaust.

 

I was just looking at this and there are some areas that were discussed in an old thread. Most of the power that can be gained seems to be from the headers. In specific, and at the time, the Tubi Euro headers were determined to be the ones that gave the greatest performance. Anything after the headers is just to mostly adjust sound, though some systems, even straight through mufflers with perforation can inhibit performance.

It was also mentioned that these will only give a great benefit if you have improved performance on your engine.

It is a 7 page thread and now a decade old, but still very pertinent:
http://www.ferrarichat.com/forum/technical-q-sponsored-algar-ferrari/124323-308-328-mondial-performance-exhaust-development.html

I think a great general statement, if you want a different sound, change the end of the exhaust and you will be fine, but don't expect some huge gain. Power made at the motor, and expensive... (crank, heads, cams, intake).

I think I'm going to get fired for spending so much time researching stuff on this website...

Cheers,
Spencer

 

That 7 page thread is a lengthy exchange of pretty pictures, interesting drawings, individual ideas and general statements about "effective header design without ONE SINGLE bit of evidence - A DYNO TEST- to support any of the opinions.

We did TONS of dyno tests on mufflers of various types on (mostly) US v8 performance cars. Not once did an aftermarket muffler consistently increase power over a new, oem muffler. Not ONCE! One particular aftermarket muffler that you could "roll a golf ball through," as someone in that 7 page thread stated was some kind of good "test" for a free-flowing muffler, reduced power over the much quieter OEM muffler. Quiet vs loud had absolutely no correlation for power.

To prevent myself from launching again into one of my favorite rants...if you want to know if a muffler or header changes the power, you need to have an INDEPENDENT shop dyno before and after with no other changes. Looking at a header or muffler and claiming that you can see that it will perform better than the existing system is incorrect.

Do NOT rely on the seller of the muffler/headers claims/dyno results. I promise they will be, at best misleading and, at worst, total BS. Ignore claims that this or that muff/header "flows better," That's a marketing-speak that has nothing to do with whether it actually produces more power on a given engine. I guarantee you I can find a header currently in production for any engine that will flow more on a test bench than the stock header/manifold but reduce the engine's power over a stock exhaust...

Uh oh, I can see I'm launching again so I'll stop now except for this:

Dyno test, Dyno Test, DYNO TEST! ;

Now, if you are talking about intake systems, dyno tests can be misleading sometimes...

 

As stated before unless your existing exhaust/cats are blocked then the only possible slight gain you will get is from weight reduction...

I replaced the exhaust on my GT4 with an X-Ost
and besides the sound the weight was close to half of the original..not sure if it would equate to any performance gain but if you were looking at saving weight then that would be a start...just keep the original exhaust.

Mine was full of previously repaired holes so wasn't worth keeping.